1. Field of the Invention
The present invention relates to a process for enhancing the fragrance qualities of ethylene glycol monoaryl ethers and, particularly, ethylene glycol monophenyl ether.
2. Description of the Prior Art
Ethylene glycol monophenyl ether, also commonly referred to as phenoxyethanol, phenoxetol, and phenyl cellosolve, is a well known commercial product obtained by the reaction of phenol and ethylene oxide in an alkaline medium. Typical processes for the monoethoxylation of phenol are described in U.S. Pat. Nos. 2,852,566, 3,354,227, 3,364,267, 3,525,773, 3,642,911 and 3,644,534.
In addition to being a highly useful antimicrobial agent (see U.S. Pat. No. 2,451,149), ethylene glycol monophenyl ether has a mild rose odor and use for food, cosmetic and pharmaceutical applications is disclosed in U.S. Pat. Nos. 1,881,200 and 2,451,149. Utilization as a fragrance chemical has, however, been limited due to the "metallic" odor generally associated with the product. The presence of the metallic note is objectionable to perfumers as it masks the pleasant rose odor and subtle fresh green nuances. The malodorous constituent(s), whose source and nature are unknown, are not removed by commercial distillation processes. Even when high purity ethylene glycol monophenyl ether which is water-white and essentially free of catalyst residue, unreacted phenol and higher ethylene oxide adducts is obtained utilizing sophisticated laboratory distillation procedures, the undesirable metallic note may still be evident.
Treatment of various industrial aliphatic alcohols with alkali metal borohydrides is known. U.S. Pat. No. 2,867,651 discloses the treatment of alcohols obtained via the Oxo process with alkali metal borohydride to destroy undesirable color producing impurities and thus make it possible to obtain water-white esters suitable as resin plasticizers. The process of U.S. Pat. No. 2,957,023 describes a similar treatment of oxo alcohols with metallic borohydrides to obtain plasticizer esters having improved color, however, the alcohol containing the alkali metal borohydride is aged for at least one day prior to esterification. ALFOL alcohols are contacted with an alkaline borohydride at a temperature in the range 500.degree. F. in accordance with the process of U.S. Pat. No. 3,860,520 to remove diols present as impurities and thus reduce the subsequent odor obtained when the alcohol is sulfated. There is no mention or suggestion in the above-cited references concerning the use of alkali metal borohydrides for treatment of ethoxylated products of any type or its possible use to provide perfume-grade chemicals.